SER. FISH rssN 0lt1- 4794 ENVIR REPOR'f 25 FISHERIES ENVIRONMENTAL REPORT SUBMISSION ON THE \ALUE OF THE ASHLEY FISHERY RESOURCES FISHERIES RESEARCH DIVISION MINISTRY OF AGRICULTURE AND FISHERIES CHRISTCHURCH Regional Water Board SUBMISSION ON THE VALUE OF THE ASHLEY FISHERY RESOURCES FISHERIES ENVIRONMENTAL REPORT NO. ?5 N.Z. MINISTRY OF AGRICULTURE AND F]SHERIES CHRISTCHURCH FISHERIES ENVIRONI'4ENTAL REPORTS This report is one of a series of reports issued by Fisheries Research Division on important issues related to environmental matters. They are issued under the following criteraa: (1) They are informal and should not be cited without the author's permission. (2) They are for límited circulation so that persons and organisations normally receiving Fisheries Research Division publications should not expect to receive copies automatically- (3) copies will be issued initialty to organisations to which the report is directly relevant. (4) copies will be issued to other appropriate organisations on request to Fisheries Research Division, Ministry of Agriculture and Fisheries, Private Bag, Christchurch. (5) These reports will be issued where a substantial report is required with a time constraintr e.9. a submission for a tribunal hearing. (6) They wiII also be issued as interim reports of on-goinq environ- mental studies for which year by year or intermittent reporting is advantageous. These interim reports will not preclude formal scientif ic publication. CONTENTS Page. 1. Introducti on I 2. Catchment Descri pt'i on 3 3. F'ish Resources of the Ashley River 5 3.1 Quinnat salmon 5 3.2 Brown trout 7 3.3 Rainbow trout I 3.4 Lamprey I 3.5 Eel s 9 3.6 Stokel I 's and common smel t 9 3.7 Inanga 9 3.8 Koaro 10 3.9 Common niver galaxias 10 3. 10 Canterbury mudfi sh 10 3. 11 Torrentfi sh 11 3.LZ Common bu'l'ly 11 3. 13 Bl ueg'il I ed bul 1y L2 3" 14 Redfinned bul ly 72 3.15 Giant bu1ly 12 3. 16 Upl and bul'ly 13 3.I7 Black flounder 13 3.18 Yellow-eyed mullet 13 3.19 Kahawai 13 4. Recreational Fisheries of the Ashley River 13 5. Effects of Low Fl ows 1B 5. 1 Habi tat I oss 19 5.2 Temperature 20 5.3 Fish passage 23 5 .4 hlater qual i ty 23 Page 6. Value of Wetlands and Estuarine Areas 26 7. D'iscussion 28 8. Recommendati ons 29 9. Acknowl edgements 31 10. Literature Cited 31 TABLES 1. F'ish of the Ashley River sYstem. 2. Opt'imum and upper lethal temperatures ('C) for 27 brown and rainbow trout. 3. Temperature record'ings ("C) at S.H.1 bridge on the Ashley R'iver. 22 4 . Fi sh mi grat'ions sub ject to di srupt'ion by ì ow summer flows. 24 5. Effects of suspended solids on fisheries. 25 FIGURES 1. The Ashley River system. 2. Mean monthly discharges for the Ash'ley River at Ashley Gorge, 1973-1981. 3. Relative popularity of some North Canterbury rivers to North Canterbury adult ang'lers. 15 1. INTRODUCTION The North Canterbury Catchment Board and Regiona'l l^Jater Board (NCCB) recent'ly released a report on the water resources of the Ashley catchment (Bowden i982). The report precedes comp'ilation and publìcation by the Board of a draft water allocation and management pìan for waters of the Ashley. Under the Fisheries Act (1908), Fisheries Research Divisíon (FRD) has responsibil'ity for research and advisory functions related to freshwater fish and fishery values. The Min'istry of Agriculture and Fisheries as a whole also has responsibiìity for management of these resources. This submission is made so that the NCCB, who are the water managers, are aware of the fish stocks and fisheries values associated with the Ash'ley River (Fig. 1). Thus, when the NCCB undertakes the task of setting minimum flows for the Ash'ley, it ìs hoped the proposed flow regime will be adequate to protect the fish and fisheries. FRD conducted some electric fishjng surveys in the Ashley R'iver during the late summer and winter of 1981, and summer 1982. The field programme was part of a comparative fisheries/hydrology study carried out iointly with Ministry of Works and Development (MtlD) ìn three Canterbury braided rjvers (Rakaia, Hurunui and Ashley). The aims were to identify ph-ysical factors that significantl._v affect the sjze and biomass of fish populations in braided rivers, and to collect habitat use data on the more common fish species present in these rivers. Surveys were carried out in selected reaches in the vicinity of S.H.1 bridge and near the Bullock Creek confluence (Fig. 1). While the data were not directed at prov'id'ing information for the NCCB's water allocation plan, they have given an ind'ication of the distrjbution of some native species in the middle and lower reaches of the Ashley and prov'ided comparative data with the Hurunui and Rakaia Rì vers . In th'is submission, FRD discusses: (i) the fish stocks of the Ashley River system LILLBURN R. km LEES VALLEY WHISTLER R. TOWNSEND R. KAREN R. MAKERIKERI R. S.HJ I t\ t I I I GLENTUI f .+ I I l" t SALTWATER cK. ASHLEY GORGE RANGIORA BRIDGE # BULLOCK CK. O OXFORD ! ASHLEY R. i I o , , PACIFIC RANGIORA I I OCEAN tT t FIGURE 1. The Ashley River system. 3. (i'i) the sports f ishery and angler usage (iì'i) the effects of low flows on the fishery (iv) the value of the Ashl ey wet'lands and estuary. (v) A series of recommendations is made. 2. CATCHI4ENT DESCRIPTION The Ashley River enters the sea approx'imate'ly 30 km north of Christchurch. The river is about 90 km in length, with a catchment area of 1340 km2 (Bowden 1982). Its headwaters lie in the Puketeraki Range, the highest po'int being Chest Peak (elevation 1934 m). In the upper reaches, the river flows through Lees Valley, between the Puketeraki Range and the Mt Thomas foothills (FiS. 1). From Lees Va11ey, the river is entrenched through the area known as Ashley Gorge, until'it emerges onto the Canterbury Plains where it flows in a braided, sh'ing'le 'loodpl f ai n . The major tributary entering the river below Ashley Gorge is the Okuku River, but the Glentui, Garry and Makerikeri Rivers also drain the foothills (Fjg. 1). A detailed description of the geology, cìimate and hydrology is gìven by Bowden (1982). Flow data are based primarì1y on flows recorded at Ashley Gorge, as other sites have proved unsuitable for long-term water level monitoring (Bowden 1982). The Ashley rises in the foothills, and because there is ljmited storage of snow and ice in the catchment, has a slightly different fìow pattern from major South Island east coast rivers. Mean annual discharge is 15.3 m3/s, with flows peaking in September and uniformly decreasing to a low in February (Fig. 2). Losses to groundwater and underflow in reaches of the river near the Rangiora Road bridge are sign'ificant. In periods of summer low flow the rjver in this area may become complete'ly dry for a distance of over 3 km, even vuhen there 4. {. 15 (f) F (5lrJ É. +10(J a/1 a Jan Feb l4ar Apr May Jun Jul Aug Sep Oct Nov FIGURE 2, Jtilean monthly discharges for the Ashley R'iver at Ashley Gorge , 1973- 1981. 5. are surface flows in the gorge and between S.H. 1 and the mouth. There appears to be no record of the Ash'ley River mouth ever clos'ing, probably because of the nature of the estuarine afea. Like most other east coast South Island rivers, the Ashley'is capabìe of spectacular floods, with cijscharges sometimes exceedinE 2000 m3ls. 3. FISH RESOURCES OF THE ASHLEY RIVER The scientific and common names of twenty-one spec'ies of fish known to jnhabìt the Ashley River s,vstem are l'isted in Table 1. The Ashley is one of three rivers whjch FR.D and IIIWD have surveyed as part of a comparatìve fisheries/hydrology study of bra'ided rivers in Canterbury. During 1981 and !982, surveys were carried out ìn selected reaches of the lower ¡iver, ìn the vjcinity of S.H.1 and near Bullock Creek. Results from the study shoul d be publ i shed i n 1983 . The Ashley was general'ly found to support large numbers and high dens'itìes of many fish species, wh'ich contrasted markedly with other larger, but simi'larìy braided, shingle rivers of the South Island's east coast. One species of native fish, the common river gaìaxias (GaLaxias vuLgaris) has been extensively studied in the Glentui River (Cadwallader 1973,1975a, 1975b, t976a, I976b, 1978) (see Sect'ion 3.9). The followjng brief notes on the life history and general biology of fish found in the Ashley River are based on the studies noted above, as we'll as stud'ies 'in other river systems. More detailed'information on the biology and ljfe h'istorjes of New Zealand's freshwater fish fauna js contained in McDowall (1978). 3.1 Qui nnat Salmon These popular introduced game fish are migratory, leav'ing fresh water as juveniles and returning from the sea to their river of orjgìn as adults, two-five years later. The fact that some return'ing adult fish exceed a metre in length 6. TABLE 1. F'ish of the Ashley Rìver system. Sc i enti fi c Name Common Name + * oncorhgnchus tshawgtscha Qu'innat sal mon + * Safmo trutta Brown trout + Sal-mo gairdnerii Rainbow trout * Geotria australis Lamprey x Anguilla austral-is Shortfinned eel * AnguiTTa dieffenbachii Longfi nned eel * stokell-ia anisodon Stokel I 's smel t * Retropinna retropinna Common smel t * GaLaxias macuLatus I nanga * Gafaxias brevipinnis Koaro Gal-axias vulgaris Common river galaxias o Neochanna buttowsius Canterbury mudfi sh * Cheimarrìchthgs fosteri Torrentf i sh * Gobiomorphus cotid.ianus Common bul 1y * Gobiomorphus hubbsi Bìuegilled bu'l'ìy * Gobiomorphus huttoni Redfi nned bul ly * Gobiomorphus gobioides Giant bul ly Gob iomorphus brev ic eps Up'land bul 1y * Rhombosofea retiatia Black fl ounder Afdriehetta forsteri Ye'l I ow-eyed mul I et Arripis trutta Ka hawa i * Mi gratory spec'ies + Introduced s pec'i e s o Not found in the ma'instem, but affected by changes to water levels.